US3965474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna for receiving VLF/LF transmission in seawater
Assignee: United States Department of the Navy
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Filing: 1975-09-26
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Granted: 1976-06-22
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Expires: 1995-09-26
Abstract
Abstract An improved device and technique for improving the reception of very low quency and low frequency transmissions in seawater. A loop antenna, wound on a ferrite core, is encapsulated in a water impermeable housing. Non-conducting elements are attached to the housing and extend outwardly therefrom to serve as barriers to conduction currents in the seawater. By varying the dimensions and number of the non-conducting members, the quality factor of the loop antenna can be increased to provide improved reception of VLF/LF signals.
Inventors
- 👤 David L. Guerrino
- 👤 Richard W. Cole, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:26
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
42 words
An apparatus for providing improved reception of very low frequency and low frequency transmissions in seawater comprising: a loop antenna; a non-conductive housing enclosing said loop antenna; and projection means attached to said housing for reducing circulating conduction currents about said antenna.
Claim 2
Independent Claim
42 words
An apparatus for providing improved reception of very low frequency and low frequency transmissions in seawater comprising: a loop antenna; a non-conductive housing enclosing said loop antenna; and projection means attached to said housing for reducing circulating conduction currents about said antenna.
Claim 3
Dependent Claim
23 words
The apparatus of claim 1 wherein said projection means comprises at least one dielectric strip attached to said housing and extending outwardly therefrom.
Claim 4
Dependent Claim
26 words
The apparatus of claim 2 wherein said at least one strip comprises a pair of dielectric strips attached diametrically opposite to one another on said housing.
Claim 5
Dependent Claim
25 words
The apparatus of claim 3 wherein each of said strips extends outward from said housing by an equal amount along the length of said strips.
Claim 6
Dependent Claim
27 words
The apparatus of claim 1 wherein said projection means comprises a dielectric plate attached to said housing to form at least one projection outward from said housing.
Claim 7
Independent Claim
59 words
A method of increasing the sensitivity of loop antennas in close proximity to a conductive medium comprising: sealing a loop antenna in a non-conductive housing; placing a conductive medium in close proximity to said housing; and attaching dielectric projections to said housing which extend outwardly therefrom so as to reduce circulating conduction currents in said medium about said antenna.
Claim 8
Independent Claim
59 words
A method of increasing the sensitivity of loop antennas in close proximity to a conductive medium comprising: sealing a loop antenna in a non-conductive housing; placing a conductive medium in close proximity to said housing; and attaching dielectric projections to said housing which extend outwardly therefrom so as to reduce circulating conduction currents in said medium about said antenna.
Claim 9
Dependent Claim
31 words
The method of claim 6 wherein said sealing step comprises sealing said antenna in a liquid impermeable housing and said placing step comprises submerging said housing in a conductive liquid medium.
Claim 10
Dependent Claim
11 words
The method of claim 7 wherein said liquid medium is seawater.
Claim 11
Dependent Claim
35 words
The method of claim 8 wherein said step of attaching comprises attaching strips to said housing such that the quality factor of the antenna can be changed by varying the width and number of strips.
Claim 12
Dependent Claim
22 words
The method of claim 8 wherein said step of attaching comprises attaching a dielectric plate to said housing to form said projections.
References Cited (Backward Citations)
US3495209A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-22 | 1979-12-22 | 1980-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-22 | 1983-12-22 | 1984-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-22 | 1987-12-22 | 1988-06-22 | $7700.00 | Window Closed / Lapsed |